Mascheroni construction

A construction done using a moveable compass
alone, named after the Italian geometer Lorenzo Mascheroni (1750-1800),
who, in his Geometria del compasso (1797), astonished the mathematical
world by showing how every compass-and-straightedge construction can be
done in this minimalist way. (Since straight lines can't be drawn with just
a compass, it's assumed that two points, obtained by arc intersections,
define a straight line.) It is now known that Georg Mohr (1640–1697)
proved the same results earlier in his obscure Euclides danicus (1672).
Mascheroni, or Mohr-Mascheroni, constructions are today primarily of interest
to puzzle enthusiasts who try to improve on the older solutions by finding
ones with fewer steps.